PowerShell: Shot and Forgot

Sometimes I want to ask PowerShell to do something long, and then notify me that the work is ready. And while I do something else.

For example like this

cp c: \ windows \ system32 -rec d :; done

(As a lengthy operation, "copy everything from c: \ windows \ system32 to d:")

The done function displays a message that says "done" and it can be seen even if your computer is locked.
This is achieved with such a simple piece of code in the profile:

[System.Reflection.Assembly] :: LoadWithPartialName ("System.Windows.Forms")
function msgBox ($ x) {
    [System.Windows.Forms.MessageBox] :: Show ($ x, 'Done!: PowerShell', 
	[Windows.Forms.MessageBoxButtons] :: OK, 
	[Windows.Forms.MessageBoxIcon] :: Information, [Windows.Forms.MessageBoxDefaultButton] :: Button1,
	[Windows.Forms.MessageBoxOptions] :: ServiceNotification
    )
}
function done () { 
    msgBox ("done")
}